INFLUENCE OF UNEVEN TIRE INFLATION PRESSURE ON VEHICLE DYNAMICS DURING BRAKING

The main problems in the operation of road transport vehicles today are related to safety, economy and environmental impact. The performances by the vehicles are closely linked to tires, their selection and the quality of their operation. Tire pressure strongly influences on the interaction between the wheels and the road, i.e. tire-road adhesion and rolling resistance. Proper tire pressure increases fuel economy, reduces the braking distance, improves vehicle control and extends the tire life. It is known that deterioration of control of the vehicle and braking efficiency and quality will reduce the safety of passengers. It is believed that uneven tire inflation pressure can significantly reduce the braking performance and vehicle stability. The purpose of this study is to determine the effect of tire inflation pressure inequality on the longitudinal and lateral acceleration of the vehicle when braking at maximum braking force. Maximum braking force of the vehicle is a function of the tire/road adhesion coefficient and the vertical load on the wheels. The value of the coefficient of tire/road adhesion in turn depends on the inflation pressure of the tire. For these reasons, it is appropriate to assess the impact of the vehicle tire pressure inequality on the braking performance. Studies have shown that the dynamics of a braked vehicle is greatly influenced by uneven tire inflation pressure. It was found that the lateral braking acceleration increased from 1.5 to 3.8 m.s(-2) at maximum braking force, when the vehicle speed was 80 km.h(-1).